Inverted Carrier Lift Device System and Method

ABSTRACT

An inverted carrier lift and method is disclosed. The inverted carrier lift includes a trolley movable along an overhead conveyor and a carrier for supporting a workpiece to undergo an assembly or manufacturing process. The carrier is movable relative to the trolley from a raised position to a lowered position by a motor engaged with a lifting mechanism on the trolley. On rotation of the motor, the carrier and supported workpiece is lowered or raised to position the workpiece in the workstation for processing. The workpiece may be disengaged by the carrier for support of the workpiece by one of many different fixtures depending on the processing. Following processing, the workpiece is re-engaged by the carrier, moved to a raised position and the trolley is transferred to a subsequent workstation.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 15/588,326 filed May 5, 2017 which claims prioritybenefit to U.S. Provisional Application No. 62/332,598, filed May 6,2016, and U.S. Provisional Application 62/433,405, filed Dec. 13, 2016,the entire contents of each application are incorporated herein byreference.

TECHNICAL FIELD

The present invention pertains generally to assembly systems,particularly of the type including conveyors defining a path of travelbetween workstations for conveying of a workpiece to one or moreworkstations positioned along the path of travel.

BACKGROUND

In automotive production lines, individual workpieces, such asautomotive body panels, frame components, etc., may be transportedbetween workstations where selected operations, such as welding or otherjoining operations, are performed by workers, robots, or otherprocessing equipment. Transporting individual workpieces to, andaccurately placing the workpieces at, a desired workstation on aproduction line poses numerous difficulties. Tooling and otherprocessing equipment at a workstation present obstacles that must beavoided by the incoming and departing workpieces. After reaching a givenworkstation, the workpieces must be accurately positioned within theworkstation to allow necessary processing operations to be performed.Efficiency and accuracy requirements of modern production lines requirethat workpiece delivery to a workstation be as rapid and precise aspossible.

In many common production lines and other assembly applications,workpieces are transported along an overhead rail, for instance amonorail. Powered roller rail systems move support trolleys or carriagesbetween various workstations. Electrical conductors can be providedalong the rail to provide power to the trolley motors. The trolleyscarry workpieces along the path defined by the rail, delivering theworkpieces to the workstations. To perform a processing operation on aworkpiece transported along an overhead rail, often a mechanism must beprovided to raise and lower the workpiece with respect to theworkstation to properly position the workpiece in the workstation. Priorpowered roller rail and trolley systems and devices used to raise andlower workpieces in a workstation include those described in U.S. Pat.No. 6,799,673; U.S. Pat. No. 9,513,625; and U.S. Patent ApplicationPublication No. 2015/0128719 assigned to the assignee of the presentinvention and all incorporated herein by reference.

Many prior known mechanisms for raising and lowering a workpiece intothe workstation have moved the entire workpiece-laden trolley along withan entire section of the overhead rail. This type of mechanism iscomplicated in design and prone to wear. For example, joints must beprovided between the fixed and moveable rail sections to disengage andre-engage the rail and/or trolley to the main conveyor mechanism. It canbe difficult to ensure that the section of rail lowered with the trolleyis properly realigned with the fixed rail sections. This negativelyimpacts the operational capacity of the production or assembly lines,for instance by causing wasteful “down-time” for repairs. In addition tothe foregoing disadvantages, many prior known mechanisms cycle atrelatively slow speeds, since the weight of the carrier, trolley, andrail must all be borne by the movement mechanism. Consequently, a needexists for a simplified lifting mechanism that meets the efficiencyrequirements of modern production and assembly lines, and which issimple in operation.

SUMMARY

The inventive inverted carrier lift device system and method is usefulto transport a workpiece along an assembly line and to selectively lowerand raise the workpiece in a predetermined area for processing ortemporary storage of the workpiece. The carrier lift may selectively andautomatically release the workpiece into a fixture or other device forprocessing and thereafter automatically re-engage the workpiece forcontinued movement along the assembly line.

In one example, the carrier includes an onboard lifting mechanism havinga ratcheting device and a tether for raising and lowering a support beamengaged with the workpiece through workpiece engaging devices. Thelifting mechanism is selectively engageable with a motor stationarilypositioned at a workstation which rotates the ratchet device to raiseand lower the workpiece. In a lowered position, the workpiece engagingdevices are automatically actuated to release the workpiece from thesupport beam into a desired holding fixture or other device for furtherprocessing or storage. Following further processing or storage of theworkpiece in the workstation, the carrier is positioned, lowered andautomatically re-engaged with the workpiece. The carrier is then raisedby the lifting mechanism and selectively moved along the assembly lineto another predetermined position.

In one example, the ratchet device includes a drum which threadinglyengages a single tether connected at both ends to the workpiece supportbeam, on rotation of the ratchet device by the motor, the tether isspooled onto, or unspooled from, the drum to raise or lower theworkpiece respectively.

In another example, the carrier is connected to a trolley engaged withand elevated or overhead conveyor for movement of the carrier along anassembly line through a plurality of workstations.

In another example, the carrier is used with a trunnion fixturepositioned in a workstation along the assembly line. At a loweredposition, the carrier positions and releases the workpiece to thetrunnion fixture which rotatably manipulates the workpiece to one ormore predetermined positions for processing of the workpiece.

The inventive method for raising and lowering a workpiece in aworkstation is useful for selectively vertically positioning a workpiecein a workstation for processing or temporary storage of the workpiece inthe workstation or other location. In one example, a carrier isconnected to a trolley engaged with an elevated or overhead carriermovable along an assembly line. The carrier selectively raises or lowersthe supported workpiece relative to the trolley to position theworkpiece on a fixture or other device positioned in the workstation.

In one example of the method, the carrier automatically releases theworkpiece into the fixture or other device and then re-engages theworkpiece following processing or storage for further movement along theassembly line.

In another example an alternate lift mechanism including an extensiondevice using scissor links is used to raise and lower the workpiece.

In another example, the actuating motor for selectively raising andlowering the workpiece is onboard the lift carrier instead ofstationarily positioned at the workstation independent of the carrier.

These and other aspects of the present disclosure are disclosed in thefollowing detailed description of the embodiments, the appended claimsand the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The description herein makes reference to the accompanying drawingswherein like reference numerals refer to like parts throughout theseveral views, and wherein:

FIG. 1 is a front perspective view of an inverted carrier lift systemused with an overhead conveyor system;

FIG. 2 is a rear perspective view of the overhead conveyor system inFIG. 1;

FIG. 3 is a front view of the overhead conveyor system in FIG. 1 with acarrier arranged in a lowered position;

FIG. 4 is a front perspective view of the overhead conveyor system inFIG. 1 with the carrier arranged in a raised position;

FIG. 5 is a partial cross-sectional view of the overhead conveyor systemtaken along section line 5-5 of FIG. 3;

FIG. 6 is an enlarged perspective view of an exemplary ratchet mechanismused in the system shown in FIG. 1;

FIG. 7 is a partial cross-sectional view of the ratchet mechanism takenalong section line 7-7 of FIG. 6 showing engagement with a tether;

FIG. 8 is a front view of an example of a ratchet coupler that may beemployed with the ratchet mechanism of FIG. 6;

FIG. 9 is a side view of the ratchet coupler of FIG. 8;

FIG. 10 is a side view of an exemplary drive motor that may be used toactuate the ratchet mechanism of FIG. 6;

FIG. 11 is a partial side view of an exemplary auxiliary latch mechanismthat may be employed with the system of FIG. 1;

FIG. 12 is a partial front perspective view of an exemplary rotary driveconfigured for rotatably driving multiple rollers used to support anexemplary trunnion fixture;

FIG. 13 is a partial front perspective view of an alternately configuredexemplary rotary drive configured for rotatably driving multiple rollersused to support the trunnion fixture in FIG. 12;

FIG. 14 is a partial front perspective view of yet another alternatelyconfigured rotary drive system configured for rotatably driving multiplerollers used to support the trunnion fixture in FIG. 12; and

FIG. 15 is a perspective view of one example of a flexible elevatedtransport carrier;

FIG. 16 is a side view of an example of the flexible elevated transportcarrier;

FIG. 17 is a side view of an alternate example of a flexible elevatedtransport carrier;

FIG. 18A is an alternate side view of the example the flexible elevatedtransport carrier of FIG. 3 shown in a raised position;

FIG. 18B is an alternate side view of the example of a flexible elevatedtransport carrier of FIG. 3 shown in a lowered position;

FIG. 19 is a side view of an alternate example of a flexible elevatedtransport carrier shown concurrently in a lowered and a raised position;

FIG. 20 is a perspective view of an example application of one exampleof a flexible elevated transport carrier;

FIG. 21 is a side view of the example shown in FIG. 20;

FIG. 22 is a side view of an example application of one example of aflexible elevated transport carrier;

FIG. 23 is an end view of an example application of one example of aflexible elevated transport carrier in use with a component buffershuttle;

FIG. 24 is a top view of one example of a flexible elevated transportcarrier showing example components;

FIG. 25 is a side view of one example of a flexible elevated transportcarrier;

FIG. 26 is a perspective view of an alternate example of the transportcarrier showing the carrier in both a raised and a lowered position;

FIG. 27 is an enlarged perspective view of a portion of the transportcarrier of FIG. 26 in a raised position;

FIG. 28 is an enlarged partial perspective view of a portion of thetransport carrier of FIG. 26;

FIG. 29 is an enlarged partial perspective view of a portion of thetransport carrier of FIG. 26; and

FIG. 30 is an enlarged alternate perspective view of a portion of thetransport carrier of FIG. 26; and

FIG. 31 is a flow chart of an example of a method for selectivelyraising and lowering a workpiece in a workstation

DETAILED DESCRIPTION

Referring to FIGS. 1-4, an example of an inverted carrier lift 10 usedwith an elevated or overhead conveyor system 20 is shown. The overheadconveyor 20 may include an elevated or overhead support frame (notshown) of any configuration suitable for supporting loads to betransported along a path of travel 21. The support frame structure mayinclude a programmable powered roller mechanism which is operable toselectively move the inverted carrier lift 10 along the path of travel21 through a plurality of workstations. Suitable frames or supportstructures are disclosed in U.S. Pat. Nos. 6,799,673; 8,201,723 and/or9,513,625.

As best seen in FIG. 2, the support frame includes brackets 22 thatsupport an elongated guide rail 24 which serves to support the invertedcarrier lift 10 and defines the path of travel 21 for the overheadconveyor 10. A plurality of powered rollers 26 (see FIG. 2) may berotatably mounted to the guide rail 24 in fixed locations spaced alongthe path of travel 21. One or more motors (not shown) may be employed torotatably drive at least a portion of the rollers 26. At least some ofthe rollers 26 may be operably associated with one another to rotatesubstantially in unison. A suitable powered roller overhead transportsystem is described in U.S. Patent No. U.S. Pat. No. 6,799,673.

The powered rollers 26 may be controlled by a programmable controlsystem used to monitor, sequence and control the movement of theindividual inverted carrier lift trolleys discussed below along anassembly line. One example of a suitable control system is described inU.S. Patent Application Publication No. US 2010/0241260 assigned to theassignee of the present invention and incorporated by reference herein.

The inverted carrier lift 10 may be selectively and precisely positionedat one or more locations in a workstation through a closed loop controlsystem including an optical reader positioned at the station and codedstrips or other devices on the carrier 27. The coded strips may bespecific to the particular carrier lift 27 or the workpiece transferredby the carrier 27 such that on a carrier 27 entering a workstation, theoptical reader scans the coded strip identifying information on thestrip, which may be particular to the specific carrier 27, and thecarrier 27 can be stopped at a predetermined or optimal position in theworkstation for the work to be performed on the workpiece. One suitabletransport monitoring, control and positioning system is disclosed inU.S. Pat. No. 7,108,189 owned by the assignee of the present inventionand is incorporated herein by reference. An example of the coded stripis shown atop rail 23 in FIG. 26. Other frame supports, overhead carriertransport devices, and monitoring, control and positioning systems knownby those skilled in the art, may be used. While the exemplary overheadconveyor system 20 is configured as a single monorail overhead system,other configurations of overhead conveyor systems may be employed,including but not limited to multi-rail systems.

As best seen in FIG. 2, the exemplary inverted carrier lift system 10includes a carrier 27 connected to a trolley 28 supported by theoverhead conveyor system 20. In the example, trolley 28 includes anelongate support member 30 including a first end 32 and a second end 34.Two or more c-shaped arms 35 (three shown) rigidly connect the supportmember 30 to the support rail 23 which, by weight of gravity,frictionally engages the rollers 26 for movement along the guide rail 24in response to rotation of the powered rollers 26. The trolley 28 ismoveable along the guide rail 24 and is selectively controllable toselectively stop at one or more workstations or assembly cells locatedalong the path of the conveyor system 20 as previously described above.The c-shaped arms 35 may be of other constructions, figurations andorientations. Other devices and methods for supporting trolley 28 on apowered overhead conveyor system, and moving the trolley 28 fromworkstation to workstation, known by those skilled in the art may beused.

The exemplary inverted carrier 27 includes a workpiece support beam 36suspended from the trolley 28 by two telescopic posts 38. The workpiecesupport beam 36 is selectively movable between a raised position, forexample, as shown in FIG. 4, and a lowered position, for example, asshown in FIGS. 1-3 along a carrier path of travel. An upper end 40 ofeach telescoping post 38 is attached to the trolley 28 support member 30and a lower end 42 is attached to the carrier 36. The telescopic posts38 are operable guide the raising and lowering of the workpiece supportbeam 36 and to restrict lateral movement of the workpiece support beam36 when moving between the raised and lowered positions.

In the example, each telescopic post 38 includes a lower post member 44slidably received within an upper post member 46. In the illustratedexemplary configuration, the upper post member 46 is shown attached tothe trolley 28 and the lower post member 44 attached to the workpiecesupport beam 36, but in practice, the orientation of the telescopingpost 38 may be inverted, such that the lower post member 44 is attachedto the trolley 28 and the upper post member 46 is attached to thecarrier 36. As illustrated, when operating the carrier 27, the lowerpost member 44 moves progressively further into the upper post member 46when moving the workpiece support beam 36 toward the raised position,and extends progressively further out from the upper post member 46 whenmoving the workpiece support beam 36 toward the lowered position. Thetelescopic post 38 may include an alternate configuration to accommodatethe design and performance requirements of a particular application.More than two telescopic posts 36 may be employed with the carrier 27.

Referring to the example carrier 27 shown in FIGS. 1 and 2, workpiecesupport beam 36 is shown as a generally horizontal support memberextending between, and attached to, the two telescopic posts 38.Workpiece support beam 36 may further include one or more auxiliary armsupports 50 attached to and extending generally outward from thehorizontal member 48. The workpiece support beam 36 may also supportinterchangeable antlers (vertical oriented fixtures or tooling posts,not shown) for carrying various configurations of workpieces (includingsubassemblies) between workstations for processing. Examples of thereferenced antlers are disclosed in U.S. Pat. No. 6,557,690 the entirecontents of which is incorporated by reference. The carrier 27 includingworkpiece beam support 36 may be moved from the raised transportposition, for example raised up close to support member 30, to a loweredtransfer position, for example as shown in FIGS. 1 and 2, when stoppedat a predetermined position at the workstation as further describedbelow. Alternate constructions, configurations and orientations ofhorizontal member 48, auxiliary arms 50 and telescopic posts 38 may beused to suit the workpiece being supported or the generalassembly/process line application.

With reference to the example shown in FIGS. 1-4, the carrier liftsystem 10 includes a lifting mechanism 52 operable for selectivelymoving the carrier 27 including workpiece support beam 36 between theraised position and lowered position. The exemplary lifting mechanism 52includes a flexible tether 54 attached to the workpiece support beam 36and engaged with a ratchet mechanism 56. The ratchet mechanism 56 may berotatably driven by a motor 57 (see FIG. 10) stationarily mounted at aworkstation and further described below to cyclically retract and extendthe tether 54 to raise and lower the workpiece support beam 36. Thetether 54 may include various configurations and materials, for example,braided steel cable, woven nylon straps, reinforced belts, chains andother devices known by those skilled in the art

In one example of the illustrated tether 54, tether 54 includes asingle, continuous member that is threaded through the ratchet mechanism56 further discussed below, and attached at both a first end 58 and asecond end 60 to the carrier 36 at a first attachment point 59 and asecond attachment point 61, respectively. A buckle 62 may be used toattach the ends 58 and 60 of the tether 54 to the carrier 36.

In the example shown, tether 54 passes through a pair of pulleys 64attached to the support member 30 spaced on either side of the ratchetmechanism 56 as generally shown. As best seen in FIG. 3, the pulley 64includes a pulley roller 66 rotatably mounted to a bracket 68 that maybe attached to the guide rail 24. A shaft 70 may be used to rotatablyconnect the pulley roller 66 to the bracket 68.

The pair of pulleys 64 may be spaced apart along the guide rail 24 by adistance that approximates the spacing between the attachment points 59and 61 of the tether 54 to workpiece support beam 36. To maximizelifting efficiency of the lifting mechanism 52, the pulleys 64 may bespaced such that portions of the tether 54 located between the pulleys64 and the tether connection points 59 and 61 are arranged substantiallyparallel to one another. A different pulley 64 spacing may be employed,but may result in reduced lifting efficiency.

Referring to FIGS. 6 and 7, the exemplary ratchet mechanism 56 isconnected to the trolley 28 support member 30. The exemplary ratchetmechanism includes a rotatable drum 72 fixedly attached to a ratchetshaft 74. The ratchet shaft 74 is rotatably mounted to a ratchet housing76 that attaches to the support member 30. To allow for generally freerotation of the drum 72 relative to the ratchet housing 76, the ratchetshaft 74 may be supported on one or more bearings (not shown) mountedwithin a bearing cup 78 attached to the ratchet housing 76.

In the example shown, the drum 72 includes a first drum end plate 80 anda second drum end plate 82. A plurality of elongate rods 84 extendbetween the first 80 and second 82 drum end plate, each rod with a firstend 86 attached to the first drum end plate 80 and an opposite secondend 88 attached to the second drum end plate 82. In one example, therods 84 may be arranged generally perpendicular to the first 80 andsecond 82 drum end plates. The rods 84 may also be arranged in a circleso as to form linear segments generally defining an outer perimeter of acylindrical-shaped structure extending between the first 80 and second82 drum end plates. In the example best seen in FIG. 7, each rod 84 isequally radially spaced from, and equally angularly spaced, relative toratchet shaft 74 as generally shown. Alternate constructions of drum 72and rods 84 may be used. For example, more or less rods 84 may be usedas well as the radial and angular position and spacing of the rods 84relative to each other and ratchet shaft 74. Alternate devices for drum72 may also be used to reel in/take-up or reel/let out the tether 54 torespectively raise or lower carrier 27.

As best seen in FIG. 7, reviewing from right to left, the tether 54 isoriented to frictionally engage several of the lower rods 84, passangularly around a portion of the ratchet shaft 74, through one of aplurality of open spaces 92 formed by pairs of immediately adjacent rods84, and then frictionally engage several of the other upper plurality ofrods 84 before passing toward the adjacent pulley 64 as generally shown.In operation, rotating the drum 72 about a rotational axis of theratchet shaft 74 causes the tether 54 to spool or reel on to, or off of,the generally cylindrical-shaped drum 72 thereby respectively raising orlowering the carrier 36. For example, using the tether 54 threadedthrough drum 72 as shown in FIG. 7, from the perspective illustrated inFIGS. 1 and 6, rotating the drum 72 in a clockwise direction will raisethe carrier 27, and rotating the drum 72 counter-clockwise will lowerthe carrier 27. Other orientations and engagement methods of tether 54relative to drum 72 may be used to suit the particular application anddesired movement of carrier 36 relative to support member 30.

Although lifting mechanism 52 is described and illustrated as includinga single continuous tether 54 threaded through the ratchet mechanism 56,alternately, two or more tethers may be used in place of the singletether 54. For example (not shown), one tether may have a first endattached to the carrier 36 at the first attachment point 59 and a secondend attached to one of the rods 84 of the ratchet mechanism 56 (or otherreel or take-up device). Similarly, a second tether (not shown) may havea first end attached to the carrier 36 at the second attachment point 61and a second end attached to one of the rods 84 of the ratchet mechanism56 (or other reel or take-up device). The lifting mechanism 52 willoperate in a similar manner to reel in or out a length of the tether(s)whether employing a single tether or multiple tethers.

Referring to FIG. 10, an example of a motor 57 is shown. The motor 57 isused to engage and selectively rotate ratcheting mechanism 56 to raiseor lower carrier 27. In the example system 10, motor 57 is stationarilymounted in a workstation in a position coordinated with a predeterminedstopping position for the carrier 27 and workpiece support beam 36. Forexample, when trolley 28 and connected carrier 27 enter a workstationand are brought to a stop at a predetermined position for properalignment of the carrier 27 and the workpiece 146 for processing at thatworkstation, for example to be lowered to the trunnion fixture describedfurther below, motor 57 is in alignment for engagement with theratcheting mechanism 56 in a manner further described below, to raise orlower the carrier 27 as predetermined for that workstation and workpiece146. In the examples illustrated herein, workpiece 146 is a passengervehicle or truck frame. Other automotive components and subassembliesmay serve as workpiece 146. It is understood that workpiece 146 mayinclude other components and subassemblies other than automotivecomponents.

Referring to FIG. 6, one example of a ratchet mechanism 56 ratchetcoupler 104 is shown. Exemplary ratchet coupler 104 includes a pair ofdiametrically opposed lobes 98 extending radially outward from theratchet shaft 74 as generally shown. In the example, each lobe 98includes angularly offset contact surfaces 102 defining diametricallyopposed radially-positioned openings 100 between the respective contactsurfaces 102. Referring to FIG. 6, in one example of a motor coupler(not shown), the motor coupler is connected to motor 57 shaft 96 (FIG.10), and includes complimentary lobe structures to abuttingly engage theratchet coupler 104 such that on rotation of the motor shaft 96, themotor coupler engages the respective contact surfaces 102 therebyequally rotating the ratchet coupler 104 and the attached drum 72.

In one example of engagement of the above described motor coupler (notshown), the motor 57, the motor shaft 96 or other structure (not shown)is actively extended in a direction toward the ratchet coupler 104 toposition the motor coupler lobes into the coordinating openings 100 inthe ratchet coupler 104 such that rotation of the motor shaft 96 equallyrotates the ratchet coupler 104 and drum 72. On completion of theprocessing at the workstation, the motor 57, coupler, shaft 96 or otherdevice is retracted in a direction away from the ratchet coupler 104 todisengage the motor coupler lobes from the ratchet coupler openings 100thereby clearing the motor coupler from the ratchet coupler 104 so thetrolley can freely move from the workstation along the path of travel21.

Referring to FIGS. 8 and 9, an alternate example of a ratchet coupler104A is shown. In the alternate example, ratchet coupler 104A isconfigured to include a slot 106 defined by walls 116 formed in an endface of the ratchet coupler 104A opposite the drum 72 so as to beaccessible and engageable by the motor coupler 108 (FIG. 10). Generallycentered within the slot 106 is a trapezoidal-shaped cam 110 havingsides 120. The cam 110 is arranged relative to the slot 106 such that aline interconnecting two opposite vertices 112 of the trapezoidal-shapedcam 110 is aligned generally parallel to a longitudinal axis of the slot106.

As best seen in FIG. 10, an alternate motor coupler 108 includes a pairof planar plates 114 spaced for coordinating position between therespective wall 116 of the slot 106 and the cam 110 when the ratchetcoupler 104A engages the motor coupler 108 as described below. Theexample motor coupler 108 is engaged with the ratchet coupler 104 byhorizontally sliding each of the plates 114 of the motor coupler 108through a respective opening 118 formed in the ratchet coupler 104Abetween the side walls 116 and the cam 110 so as to substantially alignthe motor output shaft 96 with the ratchet shaft 74. The inclinedsurfaces 120 of the cam 110 operate to guide and align the motor couplerplates 114 with the side walls 116 of the slot 106 when coupling the twomembers together.

In one example of engagement of motor coupler 108 and alternate ratchetcoupler 104A, on transfer of a carrier 27 into a workstation, thestationary motor 57 is horizontally aligned, and motor coupler 108 andratchet coupler 104A automatically positioned, such that the motorcoupler 108 planar plates 114 slidingly enter the ratchet coupler 104Athrough the respective spaces 118. On stopping of the carrier 27 at thepredetermined position in the workstation, the planar plates 114 arepositioned in abutting engagement, or are directly adjacent to, walls116 and the motor shaft 96 rotational axis is aligned with the ratchetmechanism shaft 74 rotational axis. On rotation of the motor shaft 96,the planar plates 114 abuttingly engage the walls 116 causing equalrotation of the ratchet mechanism shaft 74 and the drum 72. Oncompletion of the processing at the workstation, the motor coupler 108is automatically returned to its original position, for example, wherethe planar plates 114 are aligned or parallel with the carrier 27 pathof travel 21, such that on exiting of the carrier 27 from theworkstation, the planar plates 114 freely pass through the openings 118on the other side of the ratchet coupler 104A to clear the ratchetmechanism 104A from the motor coupler 108. Other devices, orientationsand methods for aligning and engaging and/or disengaging the describedmotor couplers from the ratchet couplers 104, 104A may be used. It isfurther understood that different lifting mechanisms 52, ratchet devices56 and drive sources such as motor 57 may be used to suit the particularapplication and performance specifications of the assembly line andsystem.

In one example of operation of the described motor couplers and ratchetcouplers 104, 104A, one or more sensors (not shown) are used to monitorand control the rotational positions of one or both of the describedmotor couplers and the ratchet couplers so that the respective couplersare properly positioned in predetermined alignment as a carrier 27enters the workstation in order to effect the respectiveengagement/disengagement scheme described above. For example, encodersmay be used in a closed-loop system to monitor the rotational positionof the motor shaft 96 and/or the ratchet shaft 74. In an example wherean encoder is used for the motor shaft 96, the encoder can be inelectronic communication, for example wired or through known wirelessprotocols, with a control system to send signals to the control systemas to the present position of the respective shafts and/or couplers. Thecontrol system can compare the received current position of the motorshaft 96 (or motor coupler) and send signals to, for example, the motor57 to ensure the motor coupler is in a position whereby the motorcoupler is to properly engage or disengage the respective ratchetcoupler 104, 104A at the proper point in time of the overall operatingsystem. In one example, the described encoder is placed in communicationwith the control system previously described and detailed in U.S. PatentApplication Publication No. US 2010/0241260. Other sensors, monitors,controllers and control systems may be used.

Referring to the exemplary ratchet mechanism 56 in FIG. 6, the ratchetmechanism 56 includes a toggle latch 122 operable to prevent unintendedmovement of the carrier 36 toward the lowered position. The exemplarytoggle latch 122 includes a toothed or splined disc 124 having aplurality of teeth 130 fixedly attached to the ratchet shaft 74. Acantilevered lever 126 may be pivotally attached to the ratchet housing76. An end 128 of the lever 126 may intermittingly engage a tooth 130formed along an outer circumference of the toothed disc 124 to preventunauthorized rotation of the drum 72 in one particular rotationaldirection. The toggle latch 122 does not operate to prevent rotation ofthe drum in an opposite direction. For example, the toggle latch 122 mayoperate to prevent counter-clockwise rotation of the drum 72 (as viewedfrom the perspective of FIG. 6) about ratchet shaft 74 when the lever126 is engaged with the tooth 130, thereby preventing lowering ofcarrier 27, while also allowing unhindered clockwise rotation of thedrum 72. Counter-clockwise rotation of the drum 72 may be enabled byrotating lever 126 thereby disengaging the lever end 128 from the tooth130. The lever 126 may be manually activated or actuated using variousmechanical and electro-mechanical actuators (not shown). Sensors (notshown) in communication with a local or centralized control systemdescribed above, may be used to monitor the position of latch 122. Otherconstructions of toggle latch 122, for example mechanical clutch orbrake devices, to prevent unauthorized rotation, or to permit selectedrotation, of drum 74 may be used as known by those skilled in the art.

With reference to FIG. 11, exemplary inverted carrier lift 10 carrier 27includes a locking mechanism 132 for securing carrier 27 in the raisedposition for travel between workstations or for other purposes. Theexemplary locking mechanism 132 includes a latch arm 134 pivotallyconnected to the support member 30 of the trolley 28. Alternatively, thelatch arm 134 may be pivotally mounted to another suitable location onthe carrier 27 or trolley 28. The latch arm 134 reciprocally pivotsabout a fixed point axis defined by a pivot pin 136 connected to thesupport member 30 by a bracket 138. The latch arm 134 may be selectivelypivoted between a latched position, as illustrated, for example, inFIGS. 4 and 11, and an unlatched position, as illustrated, for example,in FIGS. 1-3. The exemplary latch arm 134 includes a locking pin 140that may be simultaneously engaged with an aperture 142 in the upperpost member 46 and an aligned, coaxial aperture 144 in the lower postmember 44 when the carrier 27 is in the raised position. When pivoted tothe unlatched position, the locking pin 140 of the latch arm 134 isselectively disengaged from the aperture 142 in the upper post member 46and the aperture 144 in the lower post member 44, thereby enabling thecarrier to be moved toward the lowered position. The latch arm 134 maybe manually, mechanically, electrically, hydraulically, magnetically orpneumatically operated. The latch arm 134 may, for example, be biased,such as by a spring means or the like, towards the latched position.Other constructions or devices for latching, locking or otherwisepreventing unauthorized vertical movement of carrier 36 known by thoseskilled in the art may be used depending on the application andperformance specifications.

In examples of an automated latch arm 134, for example by an electricmotor or magnetically powered actuator, the motor/actuator may beconnected to a control system having a controller (not shown). Thecontrol system would be operable to monitor and/or control actuation ormovement of latch arm 134 between a latched and unlatched positionthrough energizing the motor/actuator. One or more sensors (not shown),for example mechanical or electric switches or contacts, oroptical/vision systems, may be used to monitor the position of the latcharm 134. The sensor(s) can also be in electronic communication with thecontrol system to actively monitor the position of the latch arm 134,for example, a real time, closed-loop automated monitoring and controlof the latching mechanism. The control system may include preprogrammedinstructions whereby, for example, the motor 57 cannot be energized whenthe latch arm 134 is determined or sensed to be in a latched or lockedposition. Equally, conveying system 20, the lifting mechanism 52 and/orthe ratchet mechanism 56 can also include sensors and be in electroniccommunication with the above-described local or central control system,as well as the respective individual mechanisms and systems, for asemi-automated, or fully automated, closed-loop operation for system 10.

In one example of inverted carrier lift system 10 shown in FIGS. 1-5,the workstation may include a trunnion mounted fixture 148 for engagingand supporting the workpiece 146 during a processing operation at theworkstation. In the example illustrated, the trunnion fixture 148includes a rotatable frame 150, a trunnion 152 connected to the frame150 for rotation therewith, and a drive 154, for example a rotary drivemotor. The trunnion 152 may be supported by multiple rollers 156 mountedto a base 158. The drive 154 selectively rotates the trunnion 152, theframe 150 and engaged workpiece 146 reciprocally through a predeterminedangular movement by rotatably driving the trunnion 152 relative to thebase 158 about an axis of rotation for end plates 160, 162.

In the example trunnion 152, two circular, generally disc-shaped endplates are used for engaging workpieces 146, including a first end plate160 and a second end plate 162. The frame 150 includes one end 164connected to the first end plate 160 and a second end 166 connected tothe second end plate 162. The frame 150 and/or the end plates 160 and162 may support clamps, tooling, fixtures, engagement pins, sensors andother devices for receiving, positioning and/or temporarily securing theworkpiece 146 to the trunnion 152, for example to the frame 150, duringprocessing of the workpiece 146. The workpiece 146 may be supported bythe trunnion fixture 148 between the end plates 160 and 162. Forexample, the workpiece 146 may be transferred to the trunnion fixture148, as shown, for example, in FIGS. 1 and 2.

One or more workpiece engaging devices (not shown) may be connected toand positioned relative to the frame 150 and/or the end plates 160 and162. The workpiece engaging device may include a tooling, nesting orholding fixtures, locating pins, clamps, and other devices for guiding,positioning, engaging and/or securing the workpiece 146 to the trunnionfixture 148. Both the first end plate 160 and the second end plate 162may be fitted with similar workpiece engaging devices, or with differentconfigurations or operative devices. Electric or pneumatic power and/orcontrols for the workpiece engaging devices, or for other structures ofthe trunnion fixture 148, may be directed through an aperture 168 in theend plates 160 and 162 or by other devices or structures. Control of theexemplary workpiece engaging devices may be actively monitored andcontrolled by the control systems, devices, hardware and/or software ina manner previously described, for example described in U.S. PatentApplication Publication No. US 2010/0241260. Other devices and methodsof monitoring and controlling the position and actuation of workpieceengagement devices, either locally by the workstation, or centrally inthe plant facility, may be used.

In one example of inverted carrier system 10, one or more workpieceengaging devices 147 are connected to the workpiece support beam 36and/or auxiliary arms 50 (as shown) to removably engage and secure theworkpiece 146 to the carrier 27, for example, workpiece support beam 36.In one example, on transfer of the workpiece 146 to the trunnion fixture148 for workstation processing, the one or more workpiece engagingdevices 147 are disengaged or otherwise, for example by an actuator (notshown), to release the workpiece 146 from the workpiece support beam 36and/or the auxiliary arms 150, or otherwise the carrier 27.

In one example, none of the carrier 27, lift mechanism 52, or trolley 28includes an onboard power generation devices or control systems thatrequire a power connection to operate. For example, as illustrated anddescribed above, lifting mechanism 52 does not require an onboardelectrical motor to rotate drum 72 which would require a powerconnection or hook-up when the carrier 27 is positioned in theworkstation. Rather, ratchet mechanism 56 is configured to be engaged byan electrical motor 57 which is stationarily mounted in the workstation.This is advantageous to reduce complexity of the system 10 and carrier27. A further advantage is shorter cycle times through a reduced numberof, or no required, connections of power to the trolley 28 and/orcarrier lift 27 when the trolley 28 enters and exits a workstation.

In one alternate example (not shown), remote power or signals may beused in order actuate actuator(s) (not shown) for the above-describedworkpiece engaging devices 147 mounted on the workpiece support beam 36in order disengage/engage the workpiece 146 for transfers between thecarrier 27 and the trunnion fixture 148. For example, clamps (not shown)positioned on workpiece support beam 36 used to engage workpiece 146 mayrequire electrical or pneumatic power to actuate the clamps between anopen (typically disengaged position) and a closed (typically engaged)position. In one example, on the carrier 27 positioning of the workpiece146 in the desired position, for example a fully lowered positionthereby placing workpiece 146 in the proper position on trunnion fixture148, cooperating and mating power connection modules or connectors areused on both of carrier 27 and the trunnion fixture 148 or theworkstation. For example, as described above, the trunnion fixture 148includes a power source (for example, electrical wiring harness orpneumatic tubing and valves with an end connector/module/plug/coupling)that may extend through aperture 168. Trunnion fixture 148 may furtherinclude a connector module, plug, socket or connector block verticallypositioned in the lowering travel path of the carrier 27, for examplethe path of the horizontal member 48 and/or auxiliary arms 50. Thecarrier 27, for example workpiece support beam 36, can also include acoordinating and mating power connector/block/socket/plug/coupling thatis aligned with the connector/block on the trunnion fixture 148.

On lowering of the carrier lift 27 to a position where the workpiece 146is properly positioned on the trunnion fixture 148 for processing, thecoordinating power modules/blocks on the carrier 27 and trunnion fixture148 engage thereby completing a power circuit to provide power to thecarrier 127 workpiece engaging devices to disengage the workpiece 146from the carrier 27 such that the trunnion fixture 148 fully supportsthe workpiece 146 for further processing. On completion of theworkstation processing on workpiece 146, the carrier 27 may bere-lowered into position such that the coordinating/mating powermodules/blocks re-engage thereby providing power (for exampleelectrical, data, pneumatic) to the workpiece engaging devices 147 onthe carrier 127 to re-engage the workpiece 146 and remove the workpiece146 from trunnion fixture 148 so that the carrier 127 may be transferredto a subsequent workstation for further processing. This example isadvantageous as described above due to reduced equipment and complexityof mobile carrier 27.

In one example, the workpiece engaging devices connected to the trunnionfixture 148 may be powered and operated in a similar manner through thesupply of power previously described. Monitoring, actuation and controlof the workpiece engaging devices may be made through communication ofsuch devices, or sensors in communication with the devices, by a localor central control system previously described and detailed in U.S.Patent Application Publication No. US 2010/0241260. Other devices andprocesses to engage/disengage the workpiece 146 from the carrier 27and/or provide power to the carrier 27 and/or trunnion fixture 148 maybe used.

In the example trunnion fixture 148, the end plates 160 and 162 arerotatably supported and frictionally engaged on the rollers 156 topromote selected rotational movement of the frame 150 and the end plates160 and 162 about a longitudinal axis of the trunnion mounted fixture148. In one example, an outer circumferential edge 170 of each roller156 engages an outer circumferential edge 172 of the respective endplates 160 and 162. Each roller 156 may be rotatably connected to abracket 174 fixedly attached to the base 158. Rotation of the rollers156 causes a corresponding rotation of the respective end plates 160 and162 about the longitudinal axis of the trunnion mounted fixture 148. Therollers 156 are suitably configured for supporting the weight of the endplates 160 and 162, the frame 150 and the workpiece 146 connected to thetrunnion mounted fixture 148.

The respective outer circumferences 170 and 172 of the rollers 156 andend plates 160 and 162, respectively, may include mating contours tohelp minimize axial movement of the trunnion 152 relative to the rollers156. For example, the outer circumference 170 of the rollers 156 mayinclude a recessed groove 176 that rollingly engages a correspondingconvex shaped outer circumference 178 of the end plates 160 and 162.Other contours may also be employed. The outer circumferences of therollers 156 and the end plates 160 and 162 may employ or includematerials configured to enhance traction between the rollers 156 and theend plates 160 and 162. In one example, the rollers 156 may be made ofurethane to promote frictional contact with the end plates 160 and 162.Other materials and methods of engagement may be used. Otherconstructions and methods for preventing or minimizing relative axialmovement between the end plates 160 and 162 and rollers 156 may be usedby those skilled in the art.

With continued reference to FIGS. 1 and 3, the exemplary drive 154, forexample the rotary drive motor illustrated, is operable to rotatablydrive at least one of the rollers 156 (powered rotation of both endplates 160, 162 shown in FIG. 2) and rotate the trunnion 152 about itslongitudinal axis. The drive 154 is fixedly attached to the base 158. Adrive shaft 180 (two shown) is rotatably coupled at least one of therollers 156 to the rotary drive 154. The exemplary drive shaft 180includes one or more universal joints 182 (two shown per drive shaft180) to accommodate any misalignment between an output shaft 184 of therotary drive 154 and an input shaft 186 of the roller 154. Multipledrive shafts 180 may be employed to drive multiple rollers 154. Forexample, in the illustrated exemplary configuration, a first drive shaft188 is used with output shaft 184, input shaft 186 and two universaljoints 182, to rotatably connect the rotary drive 154 to a roller 156engaging the first end plate 160 and a second drive shaft 190 issimilarly rotatably connected to the rotary drive 154 to a second roller156 engaging the second end plate 162. This particular configurationenables the rotary drive 154 to supply rotary power to both end plates160 and 162 to rotate the trunnion 152. It is not necessary, however,that both endplates 160 and 162 be rotatably driven by the rotary drive154. In practice, one or both end plates 160 and 162 may be rotatablydriven by the rotary drive 154. It is understood that other drivedevices 154 other than a rotary drive motor may be used.

In operation, the drive 154 may rotate the trunnion fixture 152 ineither rotational direction, as indicated by arrow 192 in FIGS. 1 and 2.With particular reference to FIG. 3, the rotary drive 154 may include amotor 192, which may be an electric motor, a hydraulic motor, pneumaticmotor, or another suitably configured motor or source of powerconvertible to rotational movement at the end plates 160, 162. Therotary drive 154 may further include a gear set configured to tailor theoutput torque and rotational speed of the rotary drive output shaft 184to accommodate the design and performance requirements of a particularapplication.

With reference to FIG. 12, an alternate example of the rotary drive 154Ais shown. In the example, rotary drive 154A is configured to rotatablydrive two or more rollers 156A that each engages a common end plate. Inthe exemplary configuration illustrated in FIG. 1, the rotary drive 154Ais configured to drive a single roller 156 engaging the first end plate160 and a second roller 156A engaging the second end plate 162. To helpmaximize transfer of rotational torque from the rollers 156A to the endplates 160 and 162, multiple rollers 156B may be rotatablyinterconnected, for example, by a belt 196. This arrangement causes therotatably interconnected rollers 156A, B to rotate substantially inunison and rotate the trunnion fixture 152 about its longitudinal axis.Alternatively, the rollers 156A, B may be rotatably interconnected by achain, a gear set, or another device suitable for transferringrotational torque between multiple rotary devices.

In the FIG. 12 example, the belt 196 operates to transfer rotationaltorque delivered to a first roller 156A from the rotary drive 154 to asecond roller 156B. Rotatably interconnecting multiple rollers 156A, Breduces the amount of rotational torque transferred from each individualroller to the respective end plates 160 and 162, thereby reducing thetractive force between the rollers 156A, B and the end plates 160 and162 required to rotate the trunnion 152 without slipping. In the FIG. 12example, the rollers 156A, B that engage the first end plate 160 arerotatably interconnected by the belt 196, and the rollers 156A, Bengaging the second end plate 162 are rotatably interconnected by asecond belt 196. In practice, it may not be necessary that rollers 156A,B at both ends of the trunnion 152 be rotatably interconnected.

In one example of rotary drive 154 not shown, a separate rotary drive154 may be employed to separately drive the rollers 156 associated witheach end plate 160 and 162. For example, with reference to FIG. 13, therotary drive 154B may be rotatably connected to a single roller 156Crotatably associated with the first end plate 160. Where both end plates160 and 162 are rotatably driven, a second rotary drive 154B may be usedto rotatably drive a second roller 156C associated with the second endplate 162. As mentioned previously, the two or more rollers 156associated with the same end plate may be rotatably interconnected by aseparate belt 196.

In an alternate example of rotary drive 154 shown in FIG. 14, two ormore rollers 156D may be rotatably interconnected for rotatably drivingthe trunnion fixture 152. For example, in the exemplary configurationillustrated in FIG. 14, four rollers 156D are used to rotatably drivethe trunnion fixture 152. Each roller 156D may be rotatablyinterconnected to an adjacent roller 156D by the belt 196, or anothersuitable connection device as previously described or known by thoseskilled in the art. Any one of the four rollers 156D may be rotatablyconnected to rotary drive 154C through a drive shaft 198. Rotary torqueoutput from the rotary drive 154C may be transferred to the roller 156Ddirectly connected to the rotary drive 154C by drive shaft 198 and toadjacent rollers 156D by the corresponding belts 196. In the illustratedexemplary configuration, all four rollers 156D engaging the end plate160 are rotatably interconnected, but in practice it may not benecessary that all rollers 156D engaging a particular end plate berotatably interconnected. A similar rotary drive arrangement, in whichmultiple rollers 156 are rotatably interconnected, may also be employedwith the rotary drive 154C used to simultaneously drive both end plates160 and 162, as illustrated for example, in FIG. 1.

In one example of described rotary drives 154, for example asillustrated in FIGS. 1, 13 and 14, the rotary drive is connected to acontroller 210. Controller 210 is in electronic communication with thecontrol system previously described for active monitoring and actuationby the control system for a semi or fully-automated, closed loop systemthrough one or more sensors previously described. Other devices andmethods to monitor and control rotary drive 154 may be used. Othersensors in communication with the controller 210 and previouslydescribed control system may be used with system 10. For example, asensor (not shown) may be used to determine when workpiece 146 is in apredetermined and proper position with the trunnion 154 such that rotarydrive 154 can be properly and automatically energized to rotate theworkpiece to a predetermined position for assembly operations at thatparticular workstation.

It is further understood that the described workstation and process maynot be an assembly or manufacturing workstation or area, but analternate predetermined area along the assembly line path of travel 21which serves as a temporary storage area or holding area for workpiece146 (each considered a workstation for simplicity in this disclosure).For example, the workstation may be a production line buffer whereinworkpieces that are in process are temporarily stored or racked untilneeded for the next stage of the assembly or manufacturing process.

Although shown as a trunnion fixture 148, different fixtures, tooling,racks and other movable and fixed devices suitable for supporting andsecuring workpiece 146 may be used (each referred to as a “fixture” forsimplicity herein). For example, the fixture may be an indexing storagerack for temporarily holding a plurality of workpieces, for example inan in-process buffer area or an end-of-process storage area wherecompleted parts await packaging and shipment. Other fixtures suitablefor the particular workstation or process operation known by thoseskilled in the art may be used.

With reference to FIG. 1, a sensor 200 may be employed to monitor therotational position of the trunnion 152. A suitable example for sensor200 includes an encoder in communication with a closed loop controlsystem as previously described for motor shaft 96, which preciselymeasures and monitors the rotational movement and position of an endplate 160,162.

With reference to FIGS. 1, 13 and 14, the controller 210 may be operablycoupled to the sensor 200 and the rotary drive 154. The controller 210may be configured to control rotation of the trunnion 152 throughoperation of the rotary drive 154. The final position of the carrier 36in the workstation may also be determined by the controller 200operating in conjunction with sensors in communication with the overheadconveyor system 20. The controller 210 may also control the rotary drive154 to rotate the trunnion 152 in response to various inputs, forexample, that the workpiece 146 has been placed in the trunnion mountedfixture 148 and is ready for processing, or that processing is completedand the workpiece 146 may now be oriented for reattachment to carrier 36of the overhead conveyor system 20. The controller 210 may alsocommunicate with a robot (not shown) configured to perform a processingoperation on the workpiece 146 attached to the trunnion mounted fixture148, and the carrier 27 moving along the guide rail 22. As previouslydescribed, the described trunnion fixture 148, rotary drive 154, andcarrier 27 equipment described may individually, or collectively, be inelectronic communication with a local and/or centralized control system,for example that described in U.S. Patent Application Publication No. US2010/0241260, for active monitoring, actuation and control according topreprogrammed instructions through sensors and signals to, and from,inverted carrier lift system 10.

With reference to FIGS. 1-4 and 11, the carrier 27 may be moved alongthe guide rail 24 and is controllable to stop at a workstation byappropriate switches and/or sensors and control circuitry. In oneexample, the previously described control system executes preprogrammedinstructions to the conveyor 20 to position and stop the carrier lift ata predetermined position at the workstation. In one example, opticalsensors positioned at the workstation read a coded strip in a closedloop feedback system to precisely position the carrier lift at apredetermined position at the workstation along the path of travel 21.One suitable example is described in U.S. Pat. No. 7,108,189.

The carrier 27 supports at least one workpiece 146 during movement ofthe carrier 27 along the guide rail 24 with respect to the workstation.The carrier 27 may be alternately moved between the raised position, asillustrated, for example, in FIG. 4, and the lowered position, asillustrated, for example, in FIGS. 1-3, when positioned at theworkstation. The locking mechanism 132 (FIG. 11) is provided forsecurely maintaining the carrier 27 in the raised position with respectto the trolley 28 when the latch arm 134 is arrange in the lockedposition, as illustrated, for example, in FIGS. 4 and 11. The lockingmechanism 132 enables movement of the carrier 36 to the lowered positionwhen the latch arm 134 is in the released position, as illustrated forexample, in FIGS. 1-3.

As previously described, in one example the carrier 27 is slidablyassociated with the trolley 28 so as to be moveable vertically inrelation to the trolley 28 to lower the workpiece 146 into theworkstation, and more particularly, the trunnion mounted fixture 148,without the necessity of lowering the entire overhead conveyor system20, as with some prior known mechanisms. In one example, the workpiece146 is released or disengaged from horizontal member 48 and arms 50through release of clamps or other workpiece engaging devices 147connected to horizontal member 48 and auxiliary arms 50 in engagementwith workpiece 146. The clamps or other retaining devices may beelectronically connected to and controlled by the local or centralizedcontrol system including sensors previously described above.

The workpiece 146 may be retained within the trunnion 152 by one or moreworkpiece retaining devices previously described. Once secured to thetrunnion mounted fixture 148, the workpiece 146 is ready for processing,which may include, for example, rotating the workpiece on one or morepositions, for one or more welding operations or a metal formingoperation designated for that workstation. For example, one or morerobots (not shown) may perform a welding operation on the workpiece 146supported by the trunnion mounted fixture 148. In one example, thetrunnion 152 may reposition the workpiece 146 to another positionfollowing a process. For example, following one welding operation at theworkstation, the workpiece may be rotated to another position so that asecond welding operation can occur allowing better access by the secondwelding robot.

When processing of the workpiece 146 is complete, the trunnion 152 maybe rotated by the rotary drive 154 to a predetermined rotary position inpreparation for removal from the trunnion mounted fixture 148 by thecarrier 27. The controller 210 or the local or centralized controlsystem previously described may then control the carrier 27 to engagethe workpiece 146 to the carrier 36 and remove the workpiece 146 fromthe trunnion mounted fixture 148. On completion of the predeterminedoperations at the workstation, the motor 57 (FIG. 10) may be selectivelyactuated to raise the carrier 27 and the now more complete workpiece 146back to raised position for transport to another location within themanufacturing facility. When all operations at the workstation arecomplete, the overhead conveyor 20 may be actuated and the carrier 27moved along the path of travel 21 out of the work station.

Referring to FIGS. 14-30, an alternate example of carrier lift device 10in the form of carrier lift 310 and methods of use are shown. Whereidentical or like components are disclosed and/or illustrated in priorfigures, the same reference numbers are used and not further describedexcept where noted. Where minor modifications exist, or for purposes ofsimply distinguishing different versions of the same device, capitalletters, A, B, C or D may be used. Alternately, the same base numberwith a higher number by one-hundred, two hundred or three hundred may beused. Where like components include the same or similar constructionsand/or functions, the same names are used although different referencenumbers may be assigned.

Referring to FIGS. 15, 16 and 25, an example alternate carrier 310 isshown. In the example, carrier 310 is shown in an exemplary use forsupporting and transporting vehicle components or other workpieces 146previously described, progressively assembled in a plurality ofsequential workstations 314 along an assembly line 316 defining a pathof travel 21 by the carrier 310.

The exemplary carrier lift 310 is preferably includes trolley 28 engagedwith an elevated or overhead conveyor 20 for movement of the trolley 28and carrier along an assembly line path of travel 21 as previouslydescribed for alternate carrier 10.

Still referring to FIGS. 15 and 16, the exemplary carrier lift 310 andcarrier 27A further includes an exemplary platform 346 and a workpiecesupport beam 350 having an upper surface 349 and lower surface 351 asgenerally shown. In an alternate example of support beam 36, carrier 27Aincludes support beam 350 which can be of the same or similarconstruction as workpiece support beam 36 as previously described andillustrated in FIG. 2 (collectively referred to as “workpiece supportbeam” or “support beam”). Referring to FIG. 2, an alternate example ofsupport beam 350 (not shown) includes two pairs of extension members orarms 50 transversely extending from beam 350. Arms 50 may be selectivelyconnected to, or be integral with, support beam 350 to suit the specificapplication and workpiece 146 to be supported and conveyed alongassembly line path of travel 21.

In a preferred example, support beam 350 and arms 50, or otherattachment and workpiece engaging devices, are modular in nature and canbe quickly connected and disconnected to support beam 350 to quicklychange the support beam 350 configuration to, for example, accommodatedifferent components or vehicle styles to support dynamic random buildsequences (vehicle models A, C, D, B, E), or batch build assemblysequences (vehicle models AAA, BBB, CCC, DDDD). Although shown asstraight bars, support beam 350 and extensions 50 can take other forms,shapes and configurations to suit the particular application as known bythose skilled in the art. Respective rails 30, beams 350 and arms 50 arepreferably made from aluminum or steel but can be made from othermaterials known by those skilled in the art. It is further understoodthat support beam 350 can include workpiece engagement devices 147 aspreviously described (not shown in FIGS. 15-30) to selectively, securelyand releasably engage various workpieces 146 in the manner and operationgenerally described for carrier lift 10. For example, pneumatic clampingdevices which are actuated through pressurized airlines may be used toclamp and hold a workpiece 146 until a control system actuates theclamps to release component 146 as generally described above. Otherengagement devices, mechanisms and ways to control them known by thoseskilled in the art may be used.

Referring back to FIGS. 15 and 16, exemplary carrier lift 310 andcarrier 27A includes an alternate lift mechanism 352. In the example,lift mechanism 352 includes two telescopic posts 338 having similarconstruction and function as telescopic posts 38, including a lower postmember 344 and an upper post member 345 movable along an axis of travel370, similar to lower post member 44 and upper post member 46, asgenerally described above. A stop (not shown) may be included to preventoverextension of telescopic posts 338, for example, lower post member344 extending too far and disengaging from upper post member 345.Telescopic rods 338 may include other devices within upper post member345 to assist in the control and movement of lower post member 344, forexample, bushings, bearings and/or other devices as known by thoseskilled in the art. Other constructions, configurations and positioningof telescopic posts 338 with respect to support member 30 and supportbeam 350 may be used as known by those skilled in the art.

In the example carrier lift 310 carrier 27A shown in FIG. 15 eachtelescopic post 338 includes a brace 373 connected to support member 30and upper post member 345. In one example, brace 373 assists to keep therespective post 360 in a vertical orientation and may further prevent orreduce rotation and/or linear movement in the geometric X direction(along path of travel 21) or along the geometric Y direction (transverseto path of travel 21). Other devices and mechanisms to prevent or reducerotation (rocking) or linear movement of the lift mechanism 352 relativeto the overhead conveyor 20 may be used as known by those skilled in theart.

Referring to FIGS. 17-19, and 26-30 alternate examples of carrier 310,carrier 27B and lift mechanism 352A are shown. Referring to FIGS. 17 and18A and 18B, carrier 27B and lift mechanism 352A alternately employs ascissor-type lift mechanism 426. In the example, scissors lift mechanism426 includes a first link 430 (two shown) and a second link 436 (twoshown) respectively connected to support member 30 and workpiece supportbeam 350 and each other at pivot points 440 as generally shown. First430 and second 436 links rotate about pivot points 440 to raise toposition the support beam 350, platform 346 if used, between a raisedposition 410 shown in FIG. 18A and a lowered position 416 as shown inFIG. 18B through a lift mechanism drive 355 further described below.

In the example carrier 27B and lift mechanism 352A shown in FIGS. 17 and18A and 18B, the links 430 and 436 are positioned inward toward eachother. In the alternate lift mechanism 352B and carrier 27C exampleshown in FIG. 19, the links 430 and 436 are positioned outward and awayfrom each other as generally shown (FIG. 19 showing the carrier 310 inboth the upper position 410 (in phantom line) and the lower position 416(solid line). The alternate positioning and/or configuration of scissorlinks 430 and 436 provide flexibility and packaging of the carrier lift310 and carrier 27B and C to suit and better accommodate the assemblyprocess, workpiece 146 (not shown), assembly tooling (not shown), otherequipment (not shown) positioned in the workstation 314 or alongassembly line 316, or the assembly predetermined assembly process. Links430 and 436 are preferably made from aluminum or steel, but may be madefrom other materials suitable for the application and performancespecifications as known by those skilled in the art. Although shown asusing two links 430 and 436, it is understood that a different number oflinks and/or alternate configurations of links known by those skilled inthe art may be used.

The example carriers lifts 310 and carriers 27A, B and C shown in FIGS.15-19 further include an alternate lift mechanism drive 355 used topower and control the movement of workpiece support beam 350, platform346 (if used), and workpiece 146 if connected thereto along the travelaxis 370 described above. Example lift mechanism drive 355 includes anelectrical motor 357 preferably directly engaged with a drum 372 whichis engaged with an elongate tether 354. Tether 354 is similar inconstruction, and alternative constructions, as described above fortether 54. A ratchet mechanism 356 is not preferred due to the directengagement of the motor 357 to the drum 372, but may be used where anapplication or performance requirements dictate use.

Referring to the example carrier lift 310 and carrier 27A shown in FIGS.15 and 16, exemplary elongate tether 354 is connected at a first end 358(to the left in FIG. 16) to the support beam 350, continuously extendsupwardly and coaxially through telescopic rod 338, over a pulley 406,through drum 376, over a second pulley 406 and downwardly through theother telescopic rod 338 to connect to support beam 350 at a tethersecond end 360. As described above, or in the alternative, tether 354may be a chain, braided cable, belt or other device suitable for theapplication as known by those skilled in the art. As described above fortether 54, although shown as a single tether 354, more than one tether354 may be used per lift carrier 310.

Referring to the example carrier lift 310 and carrier 27B shown in FIGS.17-19, exemplary elongate tether 354 is connected at the first end 358(to the left in FIG. 17) to the support beam 350, continuously extendsupwardly over the pulley 406, through drum 376, over a second pulley 406and downwardly to connect to support beam 350 at the tether second end360. In exemplary operation, on energizing motor 357, drum 372 rotatesso as to increase or decrease the length of tether 354 between the motor357 and first 358 and second 360 tether ends to respectively lower orraise support beam 350 and workpiece 146 if connected thereto. In oneexample, drum 372 selectively spools out tether 354 to increase theeffective length between attachment points 358 and 360 to lower supportbeam 350 or gathers and winds tether 354 to decrease the effectivelength of tether 354 to raise support beam 350 and workpiece 146 ifconnected thereto.

Referring back to FIGS. 6 and 7, in one example, carrier lift 310 liftmechanism 352 may include a ratchet mechanism 356 connected to drum 376in a similar construction and manner as previous described for alternatelift mechanism 52, ratchet mechanism 56 and drum 72 as previouslydescribed. In the exemplary carrier lift 310 and carrier 27A or B,tether 354 is engaged with drum 372 in a similar manner, and in similaralternatives, as previously described for carrier lift 10. In thealternate lift mechanism 352 shown in FIGS. 15-19, motor 357 isconnected to support member 30 as opposed to being separate from carrier310 and stationarily mounted in the workstation as described for carrierlift 10. In one example, motor 357 engages ratchet mechanism 356 toselectively rotate ratchet mechanism 357 and drum 372 to take up orgather a length of tether 354 around drum 372 to raise support beam 350,or to let out or unspool a length of tether from drum 354 to lowersupport beam 352 to a lowered position 416, or any position along theaxis of travel 370. A toggle latch 122 is used to prevent unauthorizedrotation of drum 372 raising or lowering of tether 354 as describedabove for carrier lift 10. Other devices, and alternatives, describedfor carrier lift 10 may be used for alternate carrier 310. As notedabove, in a preferred example, ratchet mechanism 356 is not used andmotor 357 is engaged directly with drum 372.

In the example lift carrier 310 and carrier 27A-D shown in FIGS. 15-19and 26-30, wherein the motor is connected to support member 30 or is“onboard” carrier 27A-D, motor 357 can be a common electrical motor witha rotating output shaft (not shown) engaged with the ratchet mechanism356 and drum 372 as previously described. Alternately, motor 357 may bea pneumatic motor, a linear motor, an inductive motor, or other motor asknown by those skilled in the art. An electrical power source to themotor 357 may also be onboard carrier 310 or connected to, for example,support member 30 and provide continuous electrical power to motor 357.Alternately, electrical power may only be supplied to motor 357 whencarrier 310 arrives and is properly positioned in workstation 314, forexample, coordinating electrically conductive contact plates orinduction devices which complete an electrical circuit between carrier310 and workstation 314. Other devices and methods of establishingelectrical power to motor 357 known by those skilled in the art may beused. Equally, other service lines, for example pressurized air,electronic and/or data communication between the workstation 314 andcarrier 310 may be employed such that the exemplary service lines areautomatically connected on arrival and positioning of carrier 310 in aworkstation 314 to power, for example, motor 357 and workpiece engagingdevices 147 connected to support beam 350. For example, pressurized airmay be used to actuate clamps positioned on support beam 350 to engageworkpiece 146. Alternately, on sensing or detecting carrier 310 ispositioned at a workstation 314 or other predetermined location alongpath of travel 21, actuators may activate and physically connect theservice lines allowing communications of electrical power, data,pneumatic, hydraulic and other service lines between workstation 314 andcarrier 310.

For example carrier lifts 10, 310, a centralized controller (not shown)connected to, or onboard, carrier 310 may be in communication with othercontrollers or actuators onboard carrier 310 to execute signals whichenergize or actuate motor 357 and workpiece engaging devices 147. Thecarrier 310 central controller may be in communication, for example hardwire or wireless protocols, with a local workstation or assembly linecontroller or an assembly plant programmable controller to send andreceive signals, data and/or instructions to actuate the motor 357 andworkpiece engaging devices 147 in a predetermined sequence as generallydescribed above or described herein. Equally, sensors (not shown) may beincluded for motor 357, workpiece engaging devices 147 and otherequipment connected to carrier lift 310 to actively monitor, in a closedloop feedback system, the precise position and/or operations status ofthe respective equipment and send signals to the local or centralizedassembly plant controllers and control system as previously describedfor carrier lift 10. The previously mentioned controllers and controlsystems may each include a central processing unit (CPU), memory storagedevices for storing preprogrammed instructions and received signalsand/or data, transmitters, receivers, input and output devices, andbuses to place the respective components in communication with eachother. Other devices for the described controllers and control systemknown by those skilled in the art may be used.

Referring to FIGS. 20 and 21, an example application and method of useof carrier lifts 10, 310 and carrier 27A, B or C (27C shown) in anassembly line 316 with two sequential workstations 314A and 314B alongthe path of travel 21. In the example, first station 314A is set up tobe a manual load inspection station including an elevated work table508. In one example, work table 508 serves as an area where operatorscan conduct manual placement of components on the table 508 for manualassembly operations or to simply position the components in holdingfixtures or other tooling for further processing or assembly. In oneexample, work table 508 includes a grid of precision through holes 509,for example every 100 millimeters (mm) in an X and Y coordinatedirection, wherein precision tooling or fixtures are secured foraccurate and precision positioning of workpieces 146 for furtherprocessing. See for example the platform or table 346/508 shown in FIG.24.

As best seen in FIG. 21, carrier lift 10, 310 (310 shown) and carrier27A, B or C (C shown) and workpiece support beam 36, 350 is positionedin a raised position 410 at an upper level 500 while table 508 ispositioned on a lower level 506 of the exemplary scaffolding or framestructure. On completion of the work by the operators in workstation314A, lift mechanism 52, 352 can be energized and workpiece support beam36, 350 can be lowered to a lower position 416 to the lower level 506,wherein workpiece engaging devices 147 are actuated to engage one ormore workpieces 146 positioned on work table 508. Lift mechanism 52, 352can them be energized to raise support beam 36, 350 with engagedworkpiece(s) 146 to a higher or raised position 410 along travel axis370 and then moved down to the next workstation 314B for furtherprocessing. In one example, workpieces 146 are loaded onto work table508 by devices other than carrier lift 10, 310, for example programmablerobots or human operators wherein carrier lift 10, 310 then engages theworkpieces and raises carrier 27A, B or C in the manner described.

In the example, workstation 314B is an automated work station which mayinclude, for example, a plurality of programmable multi-axis robots (notshown) to further conduct assembly operations on the progressivelyassembled workpiece 146. In the example workstation 314B, carrier lift10, 310 and carrier 27A, B or C (C shown) may lower support beam 36, 350and engaged workpiece 146 to a lowered position 416 to the workstationlower level 506, or to another elevation along travel axis 370, intowhat is schematically shown as a tooling area 420.

Tooling area 420 may be an area of the workstation which containsholding or welding fixtures, for example trunnion fixture 148 or otherfixtures, tooling or supports described herein, which secure workpieces146 in a predetermined position so that, for example, spot welding bythe industrial robots can take place. In one example, lift mechanism 52,352 selectively, for example through control signals sent by a local orcentral control system as described above, lowers the workpiece 146 ontothe fixtures or other tooling in tooling area 420 and then disengagesthe workpieces 146 in a manner previously described by workpieceengaging devices 147, and then is raised to so as to be clear of thetravel paths of the robots so the predetermined assembly ormanufacturing work can take place.

On completion of the predetermined work in workstation 314B, in apreferred example, the carrier 27A, B or C positioned above theworkpiece 146, rises and returns to workstation 314A to engage a new ornext workpiece positioned in workstation 314A, rises and delivers thenext workpiece in workstation 314B. The completed workpiece inworkstation 314B is retrieved by a second carrier lift 10, 310positioned in a subsequent workstation positioned downstream along pathof travel 21 to retrieve the workpiece from workstation 314B and deliverit to the next downstream workstation (not shown) along path of travel21. This process continues with the carrier lift 10/310 moving onlybetween workstations 314A and 314B as the workpiece progressively movesdown path of travel 21.

Alternately, carrier 10, 310 positioned in workstation 314B may belowered, re-engage workpiece 146 in the manner previously described, andthrough overhead conveyor 20 and trolley 28 move along the path oftravel 21 downstream to the next workstation in assembly line 316 (notback to workstation 314A as described above). In one example as shown inFIG. 21 workstation 314B, on raising the carrier 10, 310 to upper level500, further manual operations may take place prior to carrier 10, 310moving along path of travel 21 to the next workstation. It is alsounderstood that on completion of work in workstation 314B, the carrierlift 10, 310 may be moved back to workstation 314A with originalworkpiece 146 for more assembly or process work in a cyclical mannerback and forth between two or more workstations to suit the particularapplication.

Although workstation 314A and 314B are described as being manual andautomated assembly setups and functions, it is understood that theworkstations may be reversed in order, for example automated assemblyfirst then manual operations, or may be a combination of both manual andautomated operations in the same workstation depending on theapplication. It is further understood that different operations mayoccur than those described. For example, automated robots (not shown)may grasp and position workpiece 146 and place them in tooling fixturesin workstation 314A instead of manual operations depending on theapplication.

An advantage of carrier lift 310 carriers 27A, B and C and workpiecesupport beam 350 is that support beam 350 may be used to engageworkpieces 146 on the support beam 350 underside or lower surface 351(similar to support beam 36 previously described) or on the support beam350 upper surface 349. When engaged on lower surface 351, for example asshown in FIG. 1 for carrier 10, carrier 310 can then lower and place theworkpiece 146 into awaiting fixtures, for example trunnion fixture 148,and/or tooling positioned in the tooling area 420. Alternately, and withan advantage of process flexibility, when advantageous to engage andposition a workpiece 146 in an upward facing orientation on support beam350 upper surface 349, or a support platform 346 shown in FIG. 15, thisfacilitates alternate operations, for example manual assemblyworkstations.

Referring to FIG. 22 an example of an application for carrier lift 10,310 and carriers 27A, B and C (C -shown) is shown for use with avertical workpiece storage stacker or buffer 510 positioned along pathof travel 21. In the example, a workpiece stacker 510 includes a cradleor component dunnage 516 positioned in a workstation at a lower level506A, for example a tooling area 420 described above. In the example,partially assembled or completed workpieces 146 are vertically stackedor oriented pending further assembly processing or packaging andshipping. This stacking may occur anywhere along an assembly line 316path of travel 21, for example at the beginning of an assembly linewhere workpieces 146 are stored awaiting introduction to an assemblyline or at the end of an assembly line waiting to be transferred to thenext assembly line. Alternately, for example, a mid-assembly line bufferarea is needed in the event a downstream assembly line is temporarilyhalted or shut down allowing the upstream assembly line to continueoperating.

In the example, a plurality of workpieces 146 are vertically stacked asgenerally shown. Carrier lift 10, 310 is positioned in the workstation316 at an upper level 500A or raised position 410 and then loweredthrough lift mechanism 52, 352 to engage the exposed workpiece 146through, for example, actuation of workpiece engaging devices 147 asgenerally described above. Carrier 10, 310 is then raised by liftmechanism 52, 352 as described above and moved to the next workstationdown the assembly line path of travel 21. Alternately, carrier 10, 310may be used to place or deposit workpieces 146 into the stacker 510 andcradle 516 in a similar manner as placing workpieces in a fixture, forexample trunnion fixture 148, as described above.

As the exposed workpiece 146 in stacker 510 may be at different heightsdepending on the current capacity of stacker 510, sensors or othermonitoring devices may be used to signal a central controller which thencalculates the proper amount for carrier 10, 310 and support beam 36,350 to lower into tooling area 420 to properly engage the exposedworkpiece 146. Alternately, stacker 510 may include devices whichautomatically position the highest or exposed workpiece 146 at apredetermined and known height so that carrier lift 10, 310 may belowered to the same lowered position and engage workpiece 146 at a knownheight position. Other stacker devices 510, constructions, orientationsand operations known by those skilled in the art may be used.

Referring to FIG. 23, an example application of carrier lift 10, 310 inuse with an exemplary transverse powered conveyor 528 is shown. In theexample, a transverse powered conveyor 528 is positioned perpendicularor transverse to assembly line 316 path of travel 21. The exemplarypowered conveyor includes a pallet 532 which may include holdingfixtures or other tooling to support and carry workpieces 146 in a knownand predetermined position for assembly or manufacturing processing.Pallet 532 is preferably positioned on a powered roller frame transport538. In the example, the powered roller frame includes powered rollerswhich frictionally engage the pallets 532 to selectively propel thepallets 532 along a path of travel 540, to and from, an area orworkstation 314 beneath carrier 10, 310 as generally shown. In theexample, conveyor or shuttle 528 cycles to position a workpiece 146 intoposition below carrier 10, 310 whereby carrier 10, 310 and workpiecesupport beam 36, 350 is lowered to engage the workpiece 146, raise theengaged workpiece 146 and transfer the workpiece 146 to the nextworkstation 314 along path of travel 21 as previously generallydescribed. A suitable example of a powered pallet and roller transport532, 538 is the VERSAPALLET® device by Comau LLC which is described inU.S. Pat. Nos. 6,966,427; 7,232,027 and/or 6,564,440 the entire contentsof which are each incorporated herein by reference. Other conveyordevices and tooling change devices known by those skilled in the art maybe used.

In one example, conveyor 528 operates as a “first-in-first-out” type ofsystem where the workpieces 146 are kept in sequential order in theproduction assembly sequence. This is useful and advantageous to supportthe complex assembly build sequences in automotive assembly where, forexample, random or short batch build sequences described above are used.The carrier lift 10, 310 device is useful and fully supportive of thissequenced part or component delivery systems described in U.S. Pat. Nos.8,869,370 and 9,513,625 the entire contents of which are incorporatedherein by reference.

In another example of powered conveyor 528 (not shown), a second poweredroller transport 528 and pallet 532 is used on the opposite side ofcarrier lift 10, 310 (to the right of carrier 10, 310 in FIG. 23, notshown, workpieces shown in phantom line). In one example, the shownpallet and powered transport to the left and a pallet and conveyor tothe right alternatingly cycle back and forth, to the right and the left,alternatingly providing selected workpieces 146, for example 23A-D tocarrier 10, 310. In one example shown in FIG. 232, if carrier lift 10,310 requires access/engagement with component 23A, pallet 532 will moveto the right positioning component 23A within workstation 314 and intoposition to be engaged by carrier 10, 310.

In an alternate example, all of the workpieces 23 on the left transportconveyor 528 may be used or engaged and removed by carrier lift 10, 310before any from a right transport 528 (not shown) is employed andworkpieces thereon used or processed. This may be useful in batch buildassembly sequences where all of the components on one transport conveyor528 are for one vehicle body type and another transport 528 may includeworkpieces 146 for an alternate vehicle type. Other combinations,constructions and orientations of transport conveyors 528 may be used asknown by those skilled in the art.

As noted above, carrier lift 10, 310 carriers 27, 27A, B and C and thevariously described workstations 314 may include a plurality of sensordevices, for example, vision, optical, laser, pressure and limit-typeswitches, which all may be in communication with a local and/or centralcontroller as described above in a closed loop, feedback system tocontinuously monitor, control and send data to and from the carrier 10,310, so the carrier 10, 310 and assembly line is highly monitored andcontrolled for present and historical operations data.

Referring to FIG. 25, carrier lift 10, 310 also includes the ability toadjust the pitch or distance 556 between workstation 314 centerlines 550to properly position carrier 10, 310 at the various workstations 314along assembly line 316. In one example, the pitch 556 is eight (8.0)meters (m) (26 feet) and the lift or travel range 560 of carrier 10, 310workpiece support beam 36, 350 along axis of travel 370 is 1.5 meters(m) (5 feet). In one example, carrier 10, 310 is capable of travelingthe pitch distance 556 in five (5) seconds (s) or less and the lift 560in three (3) seconds (s) or less. Other distances 556, 560 and times maybe used to suit the particular application and performance requirementsas known by those skilled in the art.

Referring to FIGS. 26-30, an alternate example of a transport carrier310A, carrier 27D, and lift mechanism 352B shown in FIGS. 17 and 18A andB is illustrated. Referring to FIG. 26, carrier 27D is shown both in araised 410 (shown in phantom lines) and a lowered 416 position, althoughit is understood that support beam 350 could not be in both positions atthe same time in this example as shown for ease of illustration. Theexample carrier 27D shown in FIGS. 26-30 is of the scissors-type 426lift mechanism 352B including first link 430 and second link 436 asgenerally described above for FIGS. 17 and 18A and B. Alternate partsand assemblies may be different than examples described above asgenerally shown. A platform 346 (not shown) could also be used to suitthe particular application and workpiece(s) 146 (not shown). In theexample, the support member 30, first link 430, second link 436 are madefrom aluminum or steel including a plurality of apertures to maintainstrength and reduce weight of the individual components and system 10,310 as a whole.

In the example shown in FIGS. 26-29, alternate lifting mechanism 352B issimilar in construction and components, and the alternatives describedtherefore, as lifting mechanism 352A as described above, for examplemotor 357, ratchet mechanism 356, motor 357, drum 372 and tether 354 asillustrated in FIGS. 17-19. It is understood that the example shown inFIGS. 26-30 could also take the form of the scissors 426, includingfirst link 430 and second link 436 oriented outward as shown in FIG. 19.

As best seen in FIGS. 26, 29 and 30, carrier lift 310A carrier 27Dincludes a foot member 444 which connects to workpiece support member350 at a lower end 445 and serves as a connection or anchor pivot point440 for the second link 436. In the example, foot 444 includes anopposing upper end 446 including a locating pin 447 as generally shown.

As best seen in FIGS. 27 and 28, carrier 27D includes a guide fork 448connected to support member 30. In the example, guide fork 448 defines apair of aligned slots 449 that are sized and oriented to slidinglyreceive foot 448 locating pin 447 in the slot when the carrier 310Asupport beam 350 is positioned in a raised position 410 as generallyshown. Guide fork 448 provides the support beam 350, and any workpiece146 engaged therewith, added stability and control in the directions ofthe path of travel 21 and laterally when engaged, for example, duringtransfer of carrier lift 310 between workstations 314. Other devices,constructions, positions and orientations of guide fork 448 may be usedas known by those skilled in the art.

Referring to FIG. 27, an example of previously described lockingmechanism 132 is shown. In the example, locking mechanism 132A includesa latch arm 134A pivotally connected to guide fork 448. In one example,latch arm 134 is positioned and oriented so that a distal end or hookcan engage an aperture, or other feature, in foot 444 when in a loweredor latched position. As described above for locking mechanism 132, whenengaged with foot 444, support beam 350 cannot be lowered along travelaxis 370. Alternate locking mechanism 132A may be powered, controlledand monitored through actuators and/or sensors in communication with alocal or central control system as described above. Other devices andalternatives described for locking mechanism 132 may be used for carrier310 to suit the particular application and performance specification.

As best seen in FIGS. 27, 29 and 30, the exemplary carrier lift 310Aincludes a pair of first guide members 494 extending longitudinallyoutward from opposing ends of the workpiece support beam 350. Theexemplary carrier lift further includes a pair of second guide members496 fixed in position at the workstation. As best seen in FIGS. 29 and30, each second guide members 496 include a vertical guide channel 498for sliding receipt of the respective first guide member 494 when thecarrier is positioned in the lowered position 416 as shown in FIGS. 26,29 and 30. In the lowered position, engagement of the first guide member494 with second guide member 496 locates and securely positions theworkpiece support beam 350 and supported workpiece 146 (not shown) in adesired or predetermined position when in the workstation.

Referring to FIG. 31, an example of a method 600 for raising andlowering a workpiece 146 in a workstation using a carrier lift 10, 310is illustrated. In an example and optional first step 610, examples ofthe above-described carrier lift 10, 310 including exemplary trolley 28and carrier 27, 27A, B, C or D supporting a workpiece 146 aretransferred to a predetermined workstation. As described, the trolley 28may, as an example, be engaged with an elevated or overhead conveyor 20that selectively moves along an assembly line path of travel 21 throughone or more workstations or predetermined areas along the assembly line.In one example, the assembly line path of travel 21 includes a pluralityof sequentially positioned workstations or assembly cells, for exampleworkstations 314, where one or more assembly or manufacturing operationsare conducted on a component or subassembly serving as the workpiece146.

It further understood that the workstation could be a non-assembly ornon-manufacturing cell or area, for example a stacker or buffer 510device, work table 508, or area where workpieces 146 are temporarilystored in fixtures or racks until the workpieces are re-engaged by thecarrier 27, 27A-D for further processing or transfer along the assemblyline or to another predetermined location or area. For example, theworkstation may be a production line buffer wherein workpieces that arein process are temporarily stored or racked, for example cradle 516 inFIG. 22, until needed for the next stage of the assembly ormanufacturing process. For example, if there is stoppage along oneportion of an assembly line downstream, the upstream or prior assemblyprocess may continue and the workpieces temporarily stored in a bufferrack 516 or area until the downstream process can accept them forfurther processing. Alternately, the device 10, 310 and process 600 maydeliver and lower the workpieces 146 as described in storage racks forlonger storage, for example, completed workpieces to be packaged andshipped. Other workstations, processes and applications for carrierlifts 10, 310 and system 600 known by those skilled in the art may beused.

In an exemplary second step 620 a carrier 27, 27A-D supporting theworkpiece 146 is selectively lowered from a raised position to a loweredposition in the workstation. In an optional step 625, the carrierpositions the workpiece 146 in a fixture, tooling, rack or other devicepositioned in the workstation, for example trunnion fixture 148, worktable 508, cradle 516, or tooling 534, used to support and/or manipulatethe workpiece 146 as needed for the predetermined process or processesin the workstation. It is understood that the carrier can be lowered (orraised) and stopped at any point along the carrier vertical axis oftravel 370 suitable for the particular workstation or process. In oneexample (not shown), the carrier 27, 27A-D automatically disengages orreleases the workpiece 146 from a workpiece support beam 36, 350 throughactuation of one or more workpiece engaging devices 147 connected to thesupport beam 36, 350 as described above. It is understood that carrier37, 27A-D may begin at a lowered position and raised to the raisedposition for further processing.

In one example (not shown) the carrier 27, 27A-D is raised from thelower position away from the exemplary fixture or other devicesupporting the workpiece to provide clearance for the predeterminedprocess or operation to take place on the workpiece.

In one exemplary step (not shown), a buffer 510, cradle 516 (FIG. 22)may be indexed to expose a supported workpiece 146 along the carrier 27,27A-D travel axis 370, such that support beam 36, 350 may engage theworkpiece and transfer the workpiece to another workstation. In anotherexample (not shown), tooling 534 on a shuttle 520 (FIG. 23) may beindexed into a workstation to expose the workpiece for engagement bysupport beam 36, 350.

In the example, step 630 includes conducting a process on the workpiece.The process or operation may be, for example, welding, brazing,soldering, application of adhesive, riveting, staking, bolting,drilling, machining, polishing and other assembly and/or manufacturingprocesses, or temporary storage for example in a buffer, known by thoseskilled in the art (each considered a process or operation as usedherein). These processes may be executed by programmable industrialrobots (not shown) or other automated or semi-automated devices ormanual by an operator.

In an optional step 635 (not shown), opposite to optional step 625, thecarrier 27, 27A-C may remove the workpiece 146 from the fixture or otherworkpiece supporting device. In one example (not shown) described above,the carrier 27, 27A-D will automatically actuate workpiece engagingdevices 147 to re-engage or reacquire the workpiece 146 to support beam36, 350 so that the carrier again supports the workpiece 146. Sensorsmay be used along with power sources to determine the position of thesupport beam 36, 350 relative to workpiece 146 in order to actuate theworkpiece engaging devices 147 to re-engage or removably connect thesupport beam 36, 350 to the workpiece 146. It is understood that,depending on the application and assembly process, steps 625 and 635 canbe switched. For example, step 625 can be that carrier lift 10, 310first goes to, for example, a stacker or buffer 510, or a worktable 508,where the workpieces 146 are presently positioned and first engage theworkpieces and then removing them (versus carrying workpieces 146 intothe workstation and depositing them as first described for step 625above).

In example step 640, the carrier 27, 27A-D raises the workpiece 146 fromthe lowered position, for example 416, to a raised position, for example410, in the workstation. In one step (not shown) a locking mechanism132, 132A may be actuated to lock or prevent vertical movement of thecarrier 27, 27A-D support beam 36, 350 while in a locked position.

In an optional and exemplary step 655, the carrier lift 10, 310 istransferred from the workstation along the assembly line path of travel21 to the next predetermined workstation or location for furtherprocessing or storage. It is understood that the above steps areexemplary and that additional, or fewer, steps, and in different orderof sequence, may be used in the manners described above withoutdeviating from the present invention. In one example step not shown, theworkstation may include two sequential workstations, for exampleworkstations 314A and B (FIG. 20). One of the workstations 314A and Bmay include a manual workstation and the other may include an automatedor semi-automated workstation as described above relating to FIG. 20.The carrier 27, 27A-D may move back and forth between the workstations314A and B as needed depending on the assembly process.

All terms used in the claims are intended to be given their broadestreasonable constructions and their ordinary meanings as understood bythose skilled in the art unless an explicit indication to the contraryis made herein. In particular, use of the singular articles such as “a,”“the,” “said,” etc. should be read to recite one or more of theindicated elements unless a claim recites an explicit limitation to thecontrary.

The above drawings are not necessarily to scale and certain features maybe exaggerated, removed, or partially sectioned to better illustrate andexplain the present invention. Further, the above descriptions set forthherein are not intended to be exhaustive or otherwise limit or restrictthe claims to the precise forms and configurations shown in the drawingsand disclosed in the following detailed description.

The foregoing description relates to what is presently considered to bethe most practical embodiment. It is to be understood, however, that theinvention is not to be limited to the disclosed embodiments but, on thecontrary, is intended to cover various modifications and equivalentarrangements included within the spirit and scope of the appendedclaims, which scope is to be accorded the broadest interpretation so asto encompass all such modifications and equivalent structures as ispermitted under the law.

It is to be understood that the above description is intended to beillustrative and not restrictive. Many embodiments and applicationsother than the examples provided would be apparent to those of skill inthe art upon reading the above description. The scope of the inventionshould be determined, not with reference to the above description, butshould instead be determined with reference to the appended claims,along with the full scope of equivalents to which such claims areentitled. It is anticipated and intended that future developments willoccur in the arts discussed herein, and that the disclosed systems andmethods will be incorporated into such future embodiments. In sum, itshould be understood that the invention is capable of modification andvariation and is limited only by the following claims.

What is claimed is:
 1. A method for manipulating the position of aworkpiece in a workstation, the method comprising: transferring atrolley engaged with a conveyor along a path of travel to apredetermined position at a workstation, the trolley connected to acarrier having a workpiece support beam operable to support a workpiece;lowering the carrier relative to the trolley by a lifting mechanism froma raised position to a lowered position along a carrier axis of travelin the workstation; conducting a process on the workpiece; raising thecarrier from the lowered position to the raised position in theworkstation by the lifting mechanism; and transferring the trolley fromthe predetermined position at the workstation by the conveyor along thepath of travel.
 2. The method of claim 1 further comprising: connectinga tether to the workpiece support beam; engaging the tether with arotatable drum mounted to the trolley; and energizing a motor engagedwith the drum to selectively rotate the drum to spool a length of thetether onto the drum raising the workpiece support beam relative to thetrolley or unspool the length of the tether from the drum lowering theworkpiece support beam relative to the trolley along the carrier axis oftravel.
 3. The method of claim 2 wherein motor is stationarily mountedin the workstation, the steps of lowering or raising the workpiecesupport beam further comprising: engaging the motor with a ratchetcoupler connected to the drum when the carrier is positioned at thepredetermined position at the workstation; and selectively rotating themotor to raise or lower the workpiece support beam relative to thetrolley.
 4. The method of claim 1 wherein the carrier further comprisesone of a scissors device or a telescopic post device connected to thetrolley and the workpiece support beam, the method further comprising:extending respective of the scissors device or the telescope post devicewhen the lifting mechanism lowers the carrier to the lowered position;and contracting the respective scissors device or the telescopic postdevice when the lifting mechanism raises the carrier to the raisedposition.
 5. The method of claim 4 wherein the step of lowering thecarrier further comprises: disengaging a locking mechanism from one of afoot connected to the workpiece support beam or the telescopic postdevice permitting the lowering of the carrier from the raised positionto the lowered position.
 6. The method of claim 1 wherein the carrierfurther includes a workpiece engaging device connected to the workpiecesupport beam operable to selectively engage the workpiece, the methodfurther comprising the steps of: one of disengaging or engaging theworkpiece by the workpiece engaging device while the workpiece supportbeam is positioned at the lowered position in the workstation.
 7. Themethod of claim 6 wherein the workstation includes a stationary powersource positioned along the carrier axis of travel and the workpiecesupport beam includes a complimentary power connector in electriccommunication with the workpiece engaging device, the method furthercomprising: automatically engaging the workpiece support beam powerconnector to the stationary power source when the carrier is positionedin the lowered position; providing electric power to the workpieceengaging device to selectively actuate the workpiece engaging device toengage or disengage the workpiece.
 8. The method of claim 6 furthercomprising the steps of: engaging the workpiece with a fixturepositioned in the workstation at the carrier lowered position;disengaging the workpiece from the workpiece support beam by theworkpiece engaging device prior to conducting the process on theworkpiece; and re-engaging the workpiece to the workpiece support beamby the workpiece engaging device following conducting the process on theworkpiece.
 9. The method of claim 8 wherein the fixture positioned inthe workstation comprises a trunnion fixture, the step of conducting aprocess on the workpiece further comprises: rotating the trunnionfixture and the engaged workpiece about a trunnion fixture axis ofrotation to a predetermined rotated position for the workpiece.
 10. Themethod of claim 6 wherein the workstation comprises one of a buffer or acradle, the method further comprising the steps of: indexing the bufferor the cradle to expose the workpiece for engagement of the workpiece bythe workpiece engaging device; lowering the workpiece support beam tothe lowered position by the lifting mechanism; engaging the workpiece tothe workpiece support beam by the workpiece engaging device; andremoving the workpiece from the buffer or cradle by raising theworkpiece support beam by the lifting mechanism.
 11. The method of claim6 wherein the workstation comprises a workpiece shuttle positionedtransverse to the path of travel, the method further comprising the stepof: indexing the workpiece shuttle to expose the workpiece forengagement of the workpiece by the workpiece engaging device; loweringthe workpiece support beam to the lowered position by the liftingmechanism; engaging the workpiece to the workpiece support beam by theworkpiece engaging device; and removing the workpiece from the workpieceshuttle by raising the workpiece support beam by the lifting mechanism.12. The method of claim 1 wherein the carrier includes a scissors deviceconnected to the trolley and the workpiece support beam, a first guidemember positioned on the workpiece support beam and the workstationincludes a second guide member stationary positioned in alignment withthe first guide member, the method comprising: engaging the first guidemember with the second guide member on lowering the carrier to thelowered position to position the workpiece support member in apredetermined position in the workstation.
 13. The method of claim 1wherein the trolley includes a pair of forks, the carrier includes ascissors device connected to the trolley and the workpiece support beam,the workpiece support beam including a pair of foot members eachincluding a locating pin in alignment with the trolley forks along thecarrier axis of travel, the method comprising: engaging each footlocating pin with a respective trolley fork when the carrier is in theraised position to secure the workpiece support beam in the carrierraised position.